Optical fiber characteristic measurement device and optical fiber characteristic measurement method

Patent metadata

Field	Value
Publication number	US-11047767-B2
Application number	US-201916654264-A
Country	US
Kind code	B2
Filing date	Oct 16, 2019
Priority date	Oct 17, 2018
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

An optical fiber characteristic measurement device includes: a detector that detects Brillouin scattered light obtained by causing light to be incident on an optical fiber under test; a spectrum analyzer that obtains a Brillouin gain spectrum from the Brillouin scattered light; and a spectrum analyzing controller that: measures a characteristic of the optical fiber under test by analyzing the Brillouin gain spectrum to obtain a peak frequency of the Brillouin gain spectrum, and changes a frequency range used by the spectrum analyzer to obtain the Brillouin gain spectrum according to the peak frequency.

First claim

What is claimed is:

1. An optical fiber characteristic measurement device, comprising:
a detector that detects Brillouin scattered light obtained by causing light to be incident on an optical fiber under test;
a spectrum analyzer that obtains a Brillouin gain spectrum from the Brillouin scattered light; and
a spectrum analyzing controller that:
measures a characteristic of the optical fiber under test by analyzing the Brillouin gain spectrum to:
obtain a peak frequency of the Brillouin gain spectrum, and

changes a frequency range used by the spectrum analyzer to obtain the Brillouin gain spectrum according to the peak frequency.

2. The optical fiber characteristic measurement device of claim 1 , wherein the spectrum analyzing controller further:
predicts a possible peak frequency likely to be obtained during a subsequent measurement based on the peak frequency, and
changes the frequency range based on the possible peak frequency.

3. The optical fiber characteristic measurement device of claim 2 , wherein the spectrum analyzing controller further:
predicts the possible peak frequency using a learning model obtained by performing machine learning using data indicating change over time in the peak frequency or data indicating change over time in the Brillouin gain spectrum; and
dynamically changes the frequency range based on the possible peak frequency.

4. The optical fiber characteristic measurement device of claim 3 , wherein the spectrum analyzing controller further:
performs the machine learning so an error between the possible peak frequency and a peak frequency obtained by analyzing the Brillouin gain spectrum after changing the frequency range possible peak frequency is smaller than a predefined threshold, and
updates the learning model.

5. The optical fiber characteristic measurement device of claim 3 , wherein the spectrum analyzing controller changes the frequency range to be asymmetrical relative to the possible peak frequency.

6. The optical fiber characteristic measurement device of claim 1 , wherein the spectrum analyzing controller changes the frequency range to be narrower than a preset reference frequency range.

7. The optical fiber characteristic measurement device of claim 6 , wherein the spectrum analyzing controller, after changing the frequency range to be narrower than the reference frequency range, changes the frequency range again without changing a width of the frequency range.

8. The optical fiber characteristic measurement device of claim 1 , further comprising: a buffer that buffers temperature or strain transmission to the optical fiber under test.

9. The optical fiber characteristic measurement device of claim 1 , further comprising:
a light source that outputs frequency-modulated continuous light;
a first optical splitter that splits the continuous light into pump light and reference light; and
a second optical splitter that causes the pump light to be incident from one end of the optical fiber under test and outputs the Brillouin scattered light arising in the optical fiber under test; wherein
the detector detects interference light between the Brillouin scattered light and the reference light.

10. An optical fiber characteristic measurement method, comprising:
detecting Brillouin scattered light obtained by causing light to be incident on an optical fiber under test;
obtaining a Brillouin gain spectrum from the Brillouin scattered light; and
measuring a characteristic of the optical fiber under test by analyzing the Brillouin gain spectrum to:
obtain a peak frequency of the Brillouin gain spectrum; and

changing a frequency range used to obtain the Brillouin gain spectrum according to the peak frequency.

Assignees

• Yokogawa Electric Corp

Inventors

• Furukawa Osamu

Classifications

• G01D5/35306

  using an interferometer arrangement · CPC title

• G01M11/3172 Primary

  Reflectometers detecting the back-scattered light in the frequency-domain, e.g. OFDR, FMCW, heterodyne detection · CPC title

• G01M11/0207

  Details of measuring devices · CPC title

• G01D5/35364 Primary

  using inelastic backscattering to detect the measured quantity, e.g. using Brillouin or Raman backscattering · CPC title

• G01M11/319 Primary

  Reflectometers using stimulated back-scatter, e.g. Raman or fibre amplifiers · CPC title